PB1982: EPIDEMIOLOGICAL, CLINICAL AND THERAPEUTIC FEATURES OF CHRONIC MYELOID LEUKEMIA: EXPERIENCE OF FATTOUMA BOURGUIBA HOSPITAL OF MONASTIR
Authors: Sana Lakhel, Sarra Boukhriss, Yasmine Bnouni, Donia Bouhoula, Slama Nader, Wiem Boufrikha, Zaineb Mlayah, Adnene Laatiri
Journal: HemaSphere (2023)

Topic: 8. Chronic myeloid leukemia - Clinical Background: Chronic myeloid leukemia (CML) is a myeloproliferative disorder caused by Philadelphia chromosome. The advent of targeted therapy known as Tyrosine Kinase Inhibitors (TKIs) had revolutionized CML treatment leading to high rates of hematologic and molecular remission. Aims: Our study aimed to report the epidemiological, clinical and therapeutic features of patients with CML at Fattouma Bourguiba Hospital in Monastir. Methods: We conducted a retrospective study including patients treated for CML between 2003 and 2021. Six patients diagnosed in 2021 were not included due to the technical issues with molecular response monitoring. We referred for the European Leukemia Net (ELN) 2020 criteria to assess the response. Results: Sixty four patients were included. The median age was 49 years old (range: 12-88 years) with female predominance (sex-ratio of 0.64). At diagnosis, 85 % of patients presented no symptoms, while fatigue (7.8%) and splenomegaly-related symptoms (5%) were the most common symptoms. Physical examination showed isolated splenomegaly in 58% of patients. Lab findings have revealed in the complete blood count leukocytosis ranging from 29×109/L to 1335×109/L and neutrophilia in the range of 20×109/L to 801×109/L. Thirty two percent of patients presented with anemia while 30% presented with thrombocytosis. Peripheral blood smear was performed in all cases and showed myelemia, eosinophilia and basophilia. Three patients were diagnosed with CML in its accelerated phase. The Philadelphia chromosome was detected in the karyotype of all patients, one patient had additional chromosomal abnormalities. BCR-ABL1 transcript was detected at diagnosis by Reverse Transcriptase-Polymerase Chain Reaction with the b3a2 subtype being the most common (56% of cases). The Sokal, Hasford, Eutos and ELTS scores were high in 25.7%, 13%, 10% and 12.5% of cases, respectively. Imatinib was prescribed for 97% of patients as first line therapy. Complete hematological response was achieved in 100 % of cases. Cytogenetic response was not monitored in our study. Deep molecular response (DMR) was achieved in 59% of cases with 4% of patients achieving DMR after 6 months, 51% after one year, 34% after 18 months and 11% after 2 years. Event-Free Survival (EFS), Progression-Free Survival (PFS) and Overall Survival (OS) at five years were 63.8%, 100% and 91.4%, respectively. Second line therapy with second generation TKIs (Dasatinib or Nilotinib) was required in 35% of cases due to the treatment failure in 32% and treatment related toxicity in 3% of cases. DMR was reported in 78% of cases. Third-line therapy was needed in six patients due to the inefficacy or toxicity of second line molecule, thus Nilotinib was switched to Dasatinib and vice versa. The six patients achieved an optimal response according to ELN 2020 criteria. Summary/Conclusion: Our study showed that TKIs first and second generation are highly effective in the treatment of CML, achieving complete hematological response and high rates of molecular response and leading to good long-term outcomes for patients. Keywords: Chronic myeloid leukemia, Tyrosine kinase inhibitor, Molecular response